A high-pressure pump such as described in our commonly assigned and copending patent application Ser. No. 948,542 has a piston which is normally rapidly reciprocated in relatively short strokes by a connecting rod whose end is secured to an orbital crank for transmitting the rotary orbital motion of the crank into a reciprocating motion of the piston.
As such a piston is normally reciprocated at very high speed it is essential that all of the various sliding-contact and rolling-contact surfaces be well lubricated. Thus it is necessary to provide a lubricant film around the piston in the chamber, as well as over the ends of the connecting rod, both at the piston and at the crank. Normally such lubrication is effected by providing a separate lubricating pump connected to an independent supply of fluid and to tubing or conduits connected to or opening at the various parts to be lubricated. This separate pump continuously circulates the lubricant over the regions to be lubricated and is normally connected up so as to operate whenever the pump is operated.
Such a system is relatively complex and, therefore, contributes considerably to the cost of the pump that is employed. Furthermore such arrangements make the pump considerably more bulky, and the extra tubing, lubricant pump, and other associated parts of the system constitute structural elements which increase the likelihood of failure, as any failure of the lubricating systen will normally result in rapid destruction of the pump by overheating.